Congress keeps extending jobless benefits. But what if that only prolongs unemployment?

Have a heart. It's what Democrats like to think they do best. So President Obama's reaction to the economic crisis has been a predictable spending of trillions to soften the blow. But compassion can have consequences that aren't so compassionate  a nettlesome economic truth that now needs to be applied as Congress plans to extend unemployment benefits for the fifth time since the dark fog of recession settled in.

Continually easing the pain of jobless Americans, it turns out, can contribute to high jobless rates by warping incentives to look for work. "The consensus estimates show that unemployment benefits do prolong...